Visual function in low lighting is strong predictor of subsequent vision loss in patients with dry AMD

In a large prospective study of patients with advanced dry age-related macular degeneration (AMD), researchers found that worsening of vision in dim lighting in this patient population was a strong predictor of subsequent vision loss, according to Janet S. Sunness, MD, medical director of the Richard E. Hoover Rehabilitation Services for Low Vision and Blindness in the Greater Baltimore Medical Center.

In this NIH-funded study, 131 patients with geographic atrophy were enrolled and followed for a median of 4 years. For patients with geographic atrophy and good visual acuity at baseline, 40% lost 3 or more lines of visual acuity at 2 years follow-up and by 4 years, 27% were legally blind, reported Dr. Sunness at a media event during the American Academy of Ophthalmology annual meeting.

Visual acuity was measured at baseline under normal lighting conditions and then under low luminance to determine the low luminance deficit, she said.

More than half of the patients with more worsening in dim light at baseline lost 3 or more lines of visual acuity at 2 years compared with only 20% of patients with less worsening in dim light at baseline who lost 3 or more lines of visual acuity in the same time period.

"This test may be an early marker for improvement in macular health and may allow for more rapid screening of possible therapies for geographic atrophy," Dr. Sunness said. "It may also allow for the selection of patients at highest risk of vision loss for future geographic atrophy treatment trials."

Geographic atrophy affects 3.5% of the population of those 75 years and older. It becomes more common with age, affecting 25% of those 90 years and older.

Other topics during the press conference were the genetic epidemiology of AMD; CAPT Trial (Laser for Drusen Study); low vision care and visual rehabilitation; and the latest in AMD medications including ranibizumab (Lucentis) and the off-label drug bevacizumab (Avastin), both Genentech products.